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Backfire screen ?

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Have you guys removed the backfire screen in your air-filter cage??? I know what the screen is there for, but the chances that the filter actually catching fire are so small, I hear every single racer takes it off. For the ones who did it, did you have to jet any richer or was the difference not big enough? I know the YZFs are rich from the manufacturer, so this must kind of even it out, right? :thumbsup::devil:

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yes you can remove screen it will help twin air has a set up with cage but you can use a cage from a yz 250 or 125 it would be cheaper if your dealer treats you right you will still need to rejet to get the best out of your bike

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My YZ was so lean from the factory that it wouldn't even run until I adjusted the fuel screw. I've since gone up on the MJ, PJ, and raised the needle to richen it up and I think I finally have it where it needs to be.

Maybe its different with the 250's...

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It didnt make much of a difference in lower rpms on our 250's other than being able to rev much easier and quicker (contrary to other beliefs :thumbsup: )

The mid and top end is where the payoffs really came. I run a 190 main now compared to a 175 stock and the needle up a notch or two (I forget). However I also have a procircuit T-4 pipe that has way less back pressure than the stock pipe, and use a twin air anti-backfire filter so they play a big part in the air flow.

Another thing you can do to enhance air flow is to cut off the rear wall of the air box. It adds to making a better path for the air to flow into the carb. You can also wrap the pipes with header wrap. What that does is keep the exhaust gases hotter, and hotter gas moves faster. It helps in scavenging the cylinder so you can pack more fresh mix in there.

with all those combined it will be considerably quicker than a stock bike.

Then when you get fat and happy, try a toluene mix, and toss a 262 kit on it, and some hotcams, and a bit of porting, and ignition remapping...

The end is not in sight :devil:

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